Currently, as liquid crystal display devices having a wide viewing angle characteristic, the following liquid crystal display devices have been developed, for example: liquid crystal display devices using an IPS (In-Plane-Switching) mode or an FFS (Fringe Field Switching) mode, which are transverse electric field modes, and liquid crystal display devices using a VA (Vertical Alignment) mode.
VA-mode liquid crystal display devices include, for example, liquid crystal display devices of an MVA (Multidomain Vertical Alignment) mode in which a plurality of domains having different alignment directions of liquid crystal molecules are formed in one pixel, and liquid crystal display devices of a CPA (Continuous Pinwheel Alignment) mode in which the alignment direction of liquid crystal molecules is continuously varied around a rivet or the like formed on an electrode at a central position of the pixel.
An example of MVA-mode liquid crystal display device is described in Patent Document 1. In the liquid crystal display device described in Patent Document 1, alignment regulation means extending in two directions perpendicular to each other is provided. Owing to this, four liquid crystal domains are formed in one pixel in which an azimuthal angle of directors which are representative of the respective liquid crystal domains is 45° with respect to polarization axes (transmission axes) of a pair of polarizing plates placed in crossed Nicols. Where the azimuthal angle of 0° corresponds to a direction of the polarization axis of one of the polarizing plates and the counterclockwise direction is the positive direction, the azimuthal angles of the directors of the four liquid crystal domains are 45°, 135°, 225°, and 315°. Such a structure in which four domains are formed in one pixel is referred to as the “4-domain alignment structure” or simply as the “4D structure”.
Other examples of MVA-mode liquid crystal display device are described in Patent Documents 2, 3 and 4. The liquid crystal display devices described in these patent documents each include pixel electrodes having many tiny slits (cutouts) extending in an azimuthal angle direction of 45°-225° and an azimuthal angle direction of 135°-315° (such pixel electrodes are referred to as the “comb-shaped pixel electrodes” or “fishbone-type pixel electrodes”). The 4-domain alignment structure is realized by aligning liquid crystal molecules to be parallel to these slits.